The present invention relates to a new emulsifier system for use in enhanced (tertiary) oil recovery.
All surfactants currently under development for use in enhanced oil recovery are sodium petroleum sulfonates. While sodium petroleum sulfonates appear to hold the most promise for use as surfactants in enhanced oil recovery, they are disadvantageous for a number of reasons. For example, sodium petroleum sulfonates are produced using large quantities of sulfuric acid or sulfur trioxide, and hence specialized equipment and handling procedures are required. In addition, waste materials, i.e. acid sludges, are produced and these represent a significant waste disposal problem. Furthermore, sodium petroleum sulfonates have not shown good stability over a wide range of brine concentrations. Finally, sodium petroleum sulfonates are relatively expensive.
In view of these deficiencies, it is desirable to provide a surfactant for use in enhanced oil recovery which avoids these disadvantages.
Accordingly, it is an object of the present invention to provide a new surfactant for use in enhanced oil recovery which can be made without using sulfuric acid or sulfur trioxide, which is stable over a wide range of brine concentrations and which is inexpensive and simple to make.